An overload on the No.2 generator reportedly tripped its circuit breaker. The overload was apparently caused by the simultaneous starting of two compressors, one which is started manually and the other which is automatic. A second generator, operating in parallel with the first, experienced a voltage overload which exceeded the resistance of its circuit breaker. When the two generators shut down, the main engine stopped working. Post-occurrence tests seemed to indicate that this scenario is unlikely. Each generator can produce a maximum load of 625kW. As these generators are connected in parallel, they have a combined total capacity of 1,250kW. Before the compressors started up, the power consumption on each generator was 250kW. These compressors require 46kW each to operate. Even given the overload needed to start them up, the load applied could not have been sufficient to trip either of the circuit breakers. The generators were started up again within minutes of the grounding, and the whole system resumed operating normally. No mechanical problem was noted during subsequent tests, and there is no indication that such an overload did cause the two generators to shut down.Analysis An overload on the No.2 generator reportedly tripped its circuit breaker. The overload was apparently caused by the simultaneous starting of two compressors, one which is started manually and the other which is automatic. A second generator, operating in parallel with the first, experienced a voltage overload which exceeded the resistance of its circuit breaker. When the two generators shut down, the main engine stopped working. Post-occurrence tests seemed to indicate that this scenario is unlikely. Each generator can produce a maximum load of 625kW. As these generators are connected in parallel, they have a combined total capacity of 1,250kW. Before the compressors started up, the power consumption on each generator was 250kW. These compressors require 46kW each to operate. Even given the overload needed to start them up, the load applied could not have been sufficient to trip either of the circuit breakers. The generators were started up again within minutes of the grounding, and the whole system resumed operating normally. No mechanical problem was noted during subsequent tests, and there is no indication that such an overload did cause the two generators to shut down. The vessel experienced a complete power failure. The fact that the generators shut down caused the main engine and the steering gear to stop operating. No mechanical problem was noted on the generators and/or the electrical system after the power failure.Findings The vessel experienced a complete power failure. The fact that the generators shut down caused the main engine and the steering gear to stop operating. No mechanical problem was noted on the generators and/or the electrical system after the power failure. The CHRISTOFFER OLDENDORFF grounded because of a complete power failure on board the vessel. This power failure cannot be attributed to a mechanical problem. The cause of the complete power failure could not be determined.Causes The CHRISTOFFER OLDENDORFF grounded because of a complete power failure on board the vessel. This power failure cannot be attributed to a mechanical problem. The cause of the complete power failure could not be determined.